He told Honey G: "This is the biggest turn around I've ever seen on any artist.

"You started off with everyone hating you, including me, but this was like the Honey G concert.

"After tonight, G stands for the greatest."

Cowell's comments to Aalto were: "Your voice is dynamite. I loved you, I thought it was fantastic."

Judge Nicole Scherzinger got a shock when one of her former protege Rylan Clark frightened her by jumping out from behind her chair in a black PVC catsuit, ahead of his hosting gig on spin-off show The Xtra Factor.